Circuit breaker



J. TOTH ET AL Sept. 29, 1953 CIRCUIT BREAKER Filed Sept. 8, 1950 WITNESSES:

INVENTORS Julius Toth and Francls L.Gelzheser. BY $4/ ATTORN EY Patented Sept. .2.9, 1953 CIRCUIT BREAKER Y Julius Toth, Beaver, and Francis assignors to Electric Corporation, corporation of Pennsyl Pittsburg L. Gelzheiser, Westinghouse East Pittsburgh, Pa., a

Vania Application September 8, 1950, Serial No. 183,836

`8 Claims.

This invention relates to circuit breakers and more particularly to circuit breakers for control- 1mg lighting and moderate power circuits.

for magnetic tripping.

The novel features that are considered charinvention are set forth in par- The invention junction with In said drawing: Figure 1 is a longitudinal sectional view of a circuit breaker embodying mechanism in elevation, the breaker mechanism the closed position.

Fig. 2 is an elevational sectional View taken along line II-II of Fig. l and looking in the direction of the arrows.

Fig. 3 is an elevational sectional view through the trip device taken along line III-III of Fig. 2

gether by means of bolts I5 (only one being shown), stationary contact means Il, movable contact means I9, an operating mechanism 2l and a trip device 23.

The stationary contact I1 is rigidly secured to the inner end of a rivet 25 which extends through the base II and serves to support a terminal 2'! on the bottom of the base II. The other end of the terminal 21 is provided with suitable connecting means 29 for connecting the terminal in an electric circuit. At the opposite end base I I is a terminal 3I secured thereto by means of a rivet 33 which extends through the base and at its inner end supports the trip device The terminal The pivot 39 is supporte by means of a pair of spaced plates or frames 4i (only one being shown) rigidly supported by means of screws 43 to the bottom portion of the base, I I.

. The operating mechanism 2l comprises a releasable member 45 mounted on a pivot pin tl supported in the plates 4I. The releasable 1nem ber 45 is operatively connected to the switch arm 3l by means of a, toggle comprising toggle links 49 and 5I. The toggle link 49 is pivotally connected by means of a pivot pin 53 to the releasable member. The toggle link 5I is pivctally connected by means of a pivot pin 55 to the switch arm 3l and the two toggle links 49 and 5i are pivotallyconnected together by means of a knee pivot pin 51. Y

Also forming Va part of the operating mechanism is a U-shaped operating lever 59, the inner ends of the two legs of which are pivotally mounted in VV-shaped notches 6I formed in the plates 4I, the sidewalls of the notches 5I forming stops sulating material is mounted on the outer end of the operating lever 59 and extends through an in the cover I3, the opening 55 being substantially covered in all positions of the handle 63 by means of an arcuate portion 61 molded in tegral with the handle. Overcenter springs 69 The switch arm 31 is provided with a slot 13 through which the pin 39 extends, but in the closed position of the breaker the bottom of the slot 13 does not engage the pin 39. A spring 15 compressed between a spring seat in the base and a spring guide on the switch arm 31 biases the switch arm clockwise about the pin 55 and provides contact pressure -in the closed position of the breaker.

The contacts are manually opened and closed by manipulation of the handle 63. In order to open the contacts, the handle 63 is moved counterclockwise from the on position to the off position during which movement the operating lever 39 moves the line of action of the .overeenter springs 89 across to the left of the center line of the toggle link 49 whereupon the springs 69 bias the toggle 49-5I in a direction to cause its collapse and effect collapse of the toggle and opening of the contacts With a snap action. At the beginning of the manual opening operation the spring moves the bottom of theV slot 13 into engagement with the pin 39. Thereafter the switch arm pivots about the pin 39 as it moves to the open position. The contacts are closed manually by reverse movement of the handle B3, that is, clockwise from the oi to the on position. During this movement the line of action of the springs 69 is moved across to the right of the center line of toggle link 49 whereupon the Y springs 69 straighten the toggle dile-5| and close the contacts with a snap action.

The trip device 23 comprises a bimetal element 11 having a mounting foot 19 rigidly secured to the base by means of electrically connected by means of a flexible conductor to the switch arm 31. Also rigidly secured to the base by means of the rivet 33 is a support member 8| which, at its upper end, rigidly mounts a stationary magnetic member 8.3. Cooperating with the magnetic member V83 is a U-shaped armature 85 rigidly Secured to a Spring member 81 by welding. The spring member 81 is secured to the left or low-expansion 4side ,of the bimetal element at a end thereof by means of rivets 89. The spring 81 is generally rectangular in shape and has a rectangular opening therein through which the bimetal element 11 extends. The upper dnd of the bimetal element 11 is with a relatively large radius as indicated at 9|, the downwardly extending end 93 bearing against an adjustable stop screw or abutment 95 which threadedly engages a .metal insert 9,1 molded in the end wall of the base The highexpansion side of the bimetal element 11 is on the outside, and the proportion of the leg 93 to the main body of the bimetal element is such that when the bimetal is heated the main body 11 of the bimetal will deflect toward the leit and the leg 93 will deiiect toward the right a proportional amount and will, at all times, remain in contact with the abutment k91,.

The two side portions 99 oi the spring 81 extend upwardly and. are joined et the upper end by an integral cross portion |0|, the lower or inner portion of which is formed over and cornprises a latch surface |03 for engaging a letehine nose m5 of the releasable member 45 and restraining the releasable member in operative position. Formed inwardly from the side portions 99 of the spring member 8l et e point inst above the armature 85 is e pair of projections 01 which are engaged by the body of the bimetal element 11 upon deiiection thereof to disengage the rivet 33 and point adjacent the lower formed downwardly Y i the latch |03 from the latch nose |95 to effect release of the member 45 and automatic opening of the contacts.

As shown in Figs. 2 and 5, the armature 85 is channel shaped and surrounds three sides of bimetal element 11 to be energized by the current iiowing therethrough. The armature is provided with flanges |99 to which are suitably secured, for instance by welding, the portions 99 ci the spring member 81.

The circuit breaker is adapted to be tripped open after a time delay in response to overload currents below Ya predetermined value of, for instance, 10,09% of normal rated current and instantaneously in response to overload currents above l000% of rated current, or in response to short eireuiteeurrents The bimetal element 11 is heated in response to overload currents below the predetermined value and when heated a predetermined amount deiiects toward 'the left engaging the projections |81 and flexing the spring portions 99 to disengage the latch |93 from the nose |85 of the releasahle member 45. When the reieasable member .d5 is released, it rotates clockwise about vits pivot 41 carrying the pivot 53 for the toggle lin-k 49 across to the right of the line or action of the springs 59 whereupon the springs cause collapse of the toggle lvm-.5| and opening .0f the Gontacts. A stop member ||I mounted in the ,frames 4| provided to arrest the movement of the releasable meinber l5 in the open position,

Upon the occurrence of an overload current above the predetermined amount, or a shortecir.- cuit current, the armature 85 is energized sum.- ciently to be attracted to the fixed magnetic member 83 nexing the spring portions -99 and disengaging the latch |03 from the nose |95 to eiect instantaneous opening of the contacts.

Before the contacts may be closed following an automatic opening operation, it is necessary to reset and relatch the mechanism. This is ac- .eomplished by moving the handle 53 .counierf clockwise to ythe oil position during which movement a stud |13 in the `arcuate portion 6l thereof engages a surface H5 on the releasable member 45 and. moves the releeseble .member countercloclwise therewith. Near the end of the countercloclwise movement, the nose i535 Wipes by the latch |03 and .the inherent resilience of the spring portions 99 then move the latch |03 back to its latching position. The contacts may then be closed in the previously described manner by movement of the handle to the on position.

While the invention has been disclosed in aoeordapee with the provisions oi the patent statutes, it is io be understood that various chances in the structurel details and arrangement of parts thereof may be mede without departing from some of the essentie-l features of the invention- We claim as our invention:

l. A circuit breaker having relatively movable Contact means, .means releeseble to eieet eiltematie opening of Said .Contact .mee-11s, currentresponsive means comprising e Ufsheped bimetal element ,formed Afrom a single strip of bimeteliic material and having the higheexpansion side disposed on the outside of the u. said bimetal element having legs of unequal length and con.- nected in the circuit of theV breaker so that the longer leg and at least a portion of the shorter leg are heated by the current of the circuit, means xedly mounting the longer leg of said bimetal element, an adjustable abutment at all times cooperating with the shorter leg of said bimetal element, spring means mounted on the low-expansion side of said bimetal element adjacent the xedly mounted end thereof, said spring means having an opening therein through which the longer leg of said bimetal element extends, latch means on said spring means adjacent the high-expansion side of said bimetal element normally restraining said releasable means in operative position, and projections on said spring means engageable by said bimetal element upon thermal bending of said bimetal element to eiTect release of said releasable means and opening of said contact means.

2. A circuit breaker having relatively movable contact means, means releasable to eiiect automatic opening of said contact means, current-responsive means comprising a U-shaped bimetal element having the high-expansion side on the outside of the U and having legs of unequal length, said bimetal element being connected in the circuit of the breaker so that the longer leg and a portion of the shorter leg are heated by the current of the circuit, spring means comprising a flat spring mounted on the low-expansion side of said bimetal element and having an opening therein, the longer leg of said bimetal element extending through said opening so that the free end of said spring is disposed adjacent the high-expansion side of said bimetal element, latch operating means on said spring adjacent the free end thereof for effecting release of said releasable means, projections on said spring engageable by said bimetal element upon thermal bending of said bimetal element to eiect release of said releasable member, a movable armature mounted on said spring and surrounding three sides of said bimetal element to be energized by excessive currents owing through the bimetal element, a fixed magnetic member mounted adjacent said armature, and said armature being attracted to said fixed magnetic member when energized a predetermined amount to ex said spring and eiect instantaneous release of said releasable means.

3. A circuit breaker having relatively movable contact means, means releasable to eifect automatic opening of said contact means, current-responsive means comprising a U-shaped bimetal element having one end xedly mounted, spring means having one end xedly mounted on the low-expansion side of said bimetal element adjacent the xedly mounted end thereof, latch means on the free end of said spring means disposed adjacent the high-expansion side of said bimetal element normally releasably restraining said releasable member in operative position, said bimetal element upon thermal bending thereof engaging and bending said spring means to effect release of said releasable member.

4. A circuit breaker having relatively movable contact means and means releasable to effect automatic opening of said contact means, current-responsive means comprising a bimetal element having one end xedly mounted, spring means having one end Iixedly mounted on the low-expansion side of said bimetal element adjacent the xedly mounted end thereof, said spring means having an opening therein through which said bimetal element extends, latch means on the free end of said spring means disposed adjacent the high-expansion side of said bimetal element normally restraining said releasable means in operative position, said bimetal element bending upon thermal heating thereof in response to overload currents below a predetermined value to engage and actuate said spring means to eiect release of said releasable means, a fixed magnetic member, and a movable magnetic member mounted on said spring means, one of said magnetic members surrounding three sides of said bimetal element to be energized in response to overload currents flowing through said bimetal element, said movable magnetic member being operable when energized in response to overload currents above said predetermined value to actuate said spring means and instantaneously release said releasable means.

5. A circuit breaker having relatively movable contact means and means releasable to effect automatic opening of said contact means, current responsive means comprising a bimetal formed from la strip of bimetallic material and having one end i'ixedly mounted, spring means having a portion secured to the low-expansion side of said bimetal element adjacent the fixedly mounted end thereof, side portions extending along the edges of said bimetal element and a latching portion disposed adjacent the high-expansion side of said bimetal element, said portions of said spring means defining an opening through which said bimetal element extends, said latching portion normally restraining said releasable means in operative position, and projections on the side portions of said spring means engageable by said bimetal element upon thermal bending thereof to effect release of said releasable means.

6. A circuit breaker having relatively movable contact means and means releasable to effect automatic opening of said contact means, current responsive means comprising a bimetal element having one end xedly mounted, spring means having a portion secured to the low-expansion side of said bimetal element adjacent the fixedly mounted end thereof, said spring means having side portions extending along the edges of said bimetal element and having a latching portion disposed adjacent the high-expansion side of said bimetal element, said portions of said spring means defining an opening through which said bimetal element extends, said latching portion normally releasably restraining said releasable means in operative position, projections on release of said releasable means, a fixed magnetic member, a movable magnetic member mounted on said side portions of said spring means, one of said magnetic members surrounding three sides of said bimetal element to be energized by exreleasable means.

7. A circuit breaker having relatively movable contact means and means releasable to eliect opening of said contact means, current-responsive means comprising a bimetal element having spring means having one end supported on the low-expansion side of said bimetal element and the other end free, said spring means having an opening therein through which said bimetal element extends, latch operating means on the free end of said spring means adjacent the high-expansion side of said bimetal element for effecting release of said releasable assignee means, .and projections on said spring means engageable by said bimetal element upon thermal bending thereof to bend said spring means and thereby effect release of said releasable means and opening of said contact means.

8. A circuit breaker having relatively movable contact means :and means releasable to eiect opening of said contact means, current-responsive means comprising a bimetal element having one end supported, spring means having one end supported on the low-expansion side of said bimetal element and the other end free, said spring means having :an opening therein through which said bimetal element extends, latch operating means on the free end of said spring means adjacent the high-expansion side of said bimetal element normally restraining said releasable means in operative position, projections on said spring means engageable by said bimetal element upon thermal bending thereof to bend said spring means and to effect release of said releasable means and opening of said contact means, and electromagnetic means operable in response to excessive currents to bend said spring means and effect instantaneous release of said releasable means.

JULIUS TOTH.

FRANCIS L. GELZHEISER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,122,693 Maseng July 5, 1938 2,312,168 Jackson Feb. 23, 1943 2,312,169 Jackson Feb. 23, 1943 2,360,684 Jennings Oct. 17, 1944 2,378,648 Maseng June 19, 1945 2,426,880 Jackson et al. Sept. 2, 1947 2,494,761 Jackson et al. Jan. 17, 1950 

